Method of treating copper tops in the refining of nickel-copper matte.



ITE STATES PATENT OFFICE.

ROBERT R. MAFFETT, OF BAYONNE, NEW JERSEY, ASSIGNOR TO THE INTERNATIONALNICKEL COMPANY, OF NEW YORK, N. Y., A COR- PORATION OF NEW JERSEY.

METHOD OF TREATING COPPER TOPS IN THE REFINING OF NICKEL-COPPER MATTE.

Specification of Letters Patent.

Patented Oct. 17, 1905.

Application filed November 21, 1904. Serial No. 233,583-

l'o all whom it may concern:

Beit known that I, ROBERT R. MAFFETT, of Bayonne, in the county ofHudson and State of New Jersey, have invented a new and useful Method ofTreating Copper Tops in the Refining of N ickel-Oopper Matte, of whichthe following is a full, clear, and exact description.

In separating the sulfids of nickel and copper which constitute thematte ordinarily produced in the smelting of nickel ore it has been thepractice tosubject the molten matte to contact with sulfid of sodium,produced generally by mixing sodium sulfate and coke with the matte,smelting in a cupola-furnace and causing the copper and iron sulfidswhich are dissolved in the resulting sodium sulfid to separate under theinfluence of gravity from the heavier undissolved nickel sulfid. Thecopper-iron tops obtained in these processes of separation consist of asolution of sulfids of copper and iron in sulfid of sodium, andheretofore it has been the practice to recover the copper from such topsproduced in the first separation by smelting the tops in acupolafurnace, slagging off the sodium sulfid with an iron slag,grinding and calcining the matted copper and iron, and resmelting it toeliminate the iron. These operations are wasteful and slow, and althoughthey result in the recovery of most of the copper the sodium sulfidbeing slagged off is lost.

The purpose of my invention is to enable the constituents of the tops tobe separated in such way that the labor and time required are greatlylessened, the loss of copper reduced to a minimum, and the sodiumsolvent enabled to be recovered and used again in the separation offresh quantities of matte. I have discovered that this can beaccomplished by the following process: I take the copperiron tops fromthe nickel cupolas and pile them, preferably in a pile of about threefeet deep, in the open, where the action of the weather oxidizes thesodium sulfid to sodium sulfate. These tops are allowed to weather abouteight weeks, the greater part of the sodium sulfid in the tops beingoxidized to sodium sulfate, which is easily separated from the coppersultid and nickel sulfid contained in the tops. As soon as the topswhich have been treated in this manner are smelted the sodium sulfaterises to the top of the charge and is drawn off into pots, when it isallowed to cool and is returned to the nickel cupolas, where it is usedin place of refined salt cake. The conversion of the sodium sulfid tosodium sulfate is completed by oxidation, which is effected, preferably,by an air-blast, and the oxidation is continued until all or nearly allof the sodium sulfid is converted into sulfate, which in a coal-firedreverberatory furnace containing, say, twenty-five tons of the tops maylast twelve hours after the fusing of the charge; but the time will varywith the heatingcapacity of the furnace and the rapidity of theoxidation. When the conversion of the sodium compound to sodium sulfatehas been completed, the molten contents of the furnace may be withdrawntogether into pots or molds, when it will separate by gravity with aclean sharply-defined separation into a floating stratum of sodiumsulfate, a bottom stratum of copper sulfid carrying a small percentageof nickel sulfid, and an intermediate stratum of iron silicate which maycarry about three per cent. of copper and one and one-half per cent. ofnickel in the form of oxids. While the stratified and congealed mass iscooling and before it has entirely chilled the layers can readily beseparated from each other by tapping with a hammer. The top layer,consisting of sodium sulfate, carrying a little copper and nickel, canbe used again in the separation of matte, the iron layer can be chargeddirectly into a smelting-furnace, and the bottom layer of copper sulfid,being nearly free from iron, can be refined in a reverberatory furnacewithout need of previous calcination'.

Instead of tapping the molten products of the separating-furnacetogether and allowing them to separate in pots or molds, as describedabove, I prefer to take advantage of their stratification while in thefurnace and to tap the layers separately into different vessels, sincein this way I can obtain a more complete separation and purer products.By skimming or. tapping off the floating layer of sodium sulfate or thelayers of sodium sulfate and iron silicate and leaving the copper sulfidremaining in the furnace I may, if desired, proceed in the same furnacewith further refining of the copper.

The skilled metallurgist will be able to vary the process in many waysand to practice it in many kinds of apparatus.

. separating the sulfate, substantially as de It will be obvious thatthe oxidation may be entirely effected in the furnace, the preliminaryoxidation by weathering being omitted.

I claim 1. The method of treating copper-iron tops containing sulfids ofthese metals and the sulfid of an alkali metal, which consists inoxidizing the alkali-metal sulfid tosulfate and scribed.

2. The method of treating copper-.i'rontops containing sulfids of thesemetals-and the-sulfid of an alkali metal, which consists in oxidizingthe alkali-metal sulfid to sulfate and melting and separating thesulfate, substantially as described.

3. The method of treating copper-iron tops containing sulfids of thesemetals and the sulfid of an alkali metal, which consists in oxidizingthe alkali-metal sulfid to sulfate, melting in an oxidizing atmosphereand separating the sulfate, substantially as described.

4.. The method of treating copper-iron tops containing sulfids of thesemetals and the sullid of an alkali metal, which consists in oxidizingthe alkali-metal sulfiol to sulfate by weathering and melting andseparating the sulfate, substantially as described.

16. 'The' method of treating copper-iron tops containing sulfidsof thesemetals and the sulfid of anal-kali metal, which consists in oxidizingthe alkali-metal sulfid to sulfate by Weathering, melting in anoxidizing atmosphere and separating the sulfate, substantially asdescribed.

"7. The method of treating copper-iron tops containing sulfidsof thesemetals and the sulfid of an alkali metal, which consists in oxidizingthe alkali-metal sulfid to sulfate and melti'ng'and-separating thesulfate by gravity, substantially ;as described.

:8. The method-of treating copper-iron tops containin-gsulfids of thesemetals and thesulfidofan alkali metal, which consists .in oxidizing-thealkali-metal sulfid tosulfate,.meltingin-an oxidizing-atmosphere andseparating :the sulfate by gravity, substantially as described.

9. The-method of treating copper-iron tops containing sulfids of thesemetals and the-sulfid of :an alkali metal, which consists inoxidizingthe alkali-metal snlfid to sulfate, separating the sulfate bygravity, and heating and refining the copper, substantially asdescribed.

In testimony whereof I have hereunto set my hand.

ROBERT E. MAFFETT. Witnesses:

HoRAon RoBERsoN, MICHAEL A. OHARE.

